1. Field of Invention
This invention relates climate control sensors and more particularly to a method for determining if the output of the sensor is a true sensor fault or as a result of extreme temperature conditions.
2. Prior Art
U.S. Pat. No. 4,660,386 entitled Diagnostic System for Detecting Faulty Sensors in Liquid Chiller Air Conditioning System issued on Apr. 28, 1987 to Hansen et al. measures pressure into an evaporative core and the temperature out of the evaporative core. In this patent, the temperature in the evaporative core is based on the pressure of the refrigerant. The system then compares the temperature into the core with the temperature out of the core and by such comparison, the system will determine if one of the sensors is faulty.
U.S. Pat. No. 5,423,188 entitled Process for Detecting Out-Of-Range Thermistor issued on Jun. 13, 1995 to Neeley measures the ambient temperature and the cooling coil temperature. The system expects the difference between these two sensors to be within a certain range and if outside the range, the system sets an error code.
U.S. Pat. No. 4,381,549 issued on Apr. 26, 1983 to Stamp, Jr. et al. and entitled Automatic Fault Diagnostic Apparatus for a Heat Pump Air Conditioning System measures the temperature both upstream and down stream of a component such as a compressor, heat exchanger, etc. The system uses the measured temperatures to determine if the component is faulty.
U.S. Pat. No. 4,441,329 issued to Dawley on Apr. 10, 1984 and entitled Temperature Control System measures the temperature and sets an alarm if the temperature reading is outside of an expected range.
U.S. Pat. No. 5,549,152, issued on Aug. 27, 1996, and entitled Method and System for Modifying a Linear Control Algorithm Which Controls an Automotive HVAC System to Davis, Jr. et al. and assigned to a common assignee. This patent defines a system that controls a vehicle climate control system with fuzzy logic rather than linear logic.
U.S. Pat. No. 5,613,370 entitled Off-Road Cooling Control issued on Mar. 25, 1997 to Pichotta, discloses a basic vehicle climate control system.